Carrier Condensor Fan

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  #1  
Old 03-04-14, 12:42 PM
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Carrier Condensor Fan

Unit: 10-15 year old Carrier Heat Pump Model: 38YCA048300

Symptoms: Condensor Fan was squelling (at times) and running sporadicly. Motor had tons of in/out play in the shaft.

Repairs: Replaced fan motor and dual run capacitor.

Continuing issue: Can't figure the off/on sequence of fan motor. The heat pump seems to operated correctly but the fan will shut down during normal run mode (house heating). I can't say that i've been able to nail down a pattern but have seen it stop after about five minutes of running. The fan does not seem to run during the defrost cycle. Been too cold to test in cooling mode.

Could it be: The defrost thermostat. The whole unit has been icy - the coils are defrosting fast during the cycle but the bottom of unit gets very iced-up due to the runoff refreezing. The defrost thermostat looks to be on a coil at the very bottom of the unit where ice builds up. Symptoms seems to remain the same on days warm enough to melt away the buildup.

Thanks
 
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Old 03-04-14, 07:09 PM
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The condensor fan doesn't run during defrost and may not always run in heat mode.
 
  #3  
Old 03-05-14, 11:12 AM
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Does the compresser keep running when the fan shuts down?
 
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Old 03-05-14, 11:15 AM
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The compressor runs and reverses correctly.
 
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Old 03-05-14, 11:24 AM
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Could be going off on internal overloads. Is the coil clean?
 
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Old 03-05-14, 11:33 AM
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They are not visibility dirty - have been cleaned in the past. I will clean the coil this weekend when the weather warms.

Would only the fan shut off and the compressor run on?
 
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Old 03-05-14, 11:55 AM
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Yes, The compresser would not know the fan has shut down.
 
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Old 03-05-14, 12:01 PM
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So you mean internal overloads within the motor - not a signal from the board.
 
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Old 03-05-14, 02:09 PM
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Yes the internal overloads. If there is not enough air flow the motor will heat up. As for the defrost thermostat, I would mount it right past the TXV (Thermostatic Expansion Valve).

On a heat pump the fan wire is run through the defrost board to stop the fan in defrost mode. It is possilble that the defrost module is faulty and turning the fan off.
 
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Old 03-05-14, 09:12 PM
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I have not read anything about the unit not heating in this thread.
If it is heating fine then this is the normal operation of a heat pump as PJ has already posted.

If you Google heat pump defrost cycle video, it might help.
 
 

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